CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net income	$ 4,872	$ 6,560	$ 7,374	$ 22,286
Other comprehensive income (loss), net of tax:
Currency translation	4,364	1,720	(5,754)	1,695
Total other comprehensive income (loss), net	5,324	2,472	(3,831)	3,205
Comprehensive income	10,196	9,032	3,543	25,491
Comprehensive income attributable to noncontrolling interest	283	682	875	1,204
Comprehensive income attributable to NL stockholders	9,913	8,350	2,668	24,287
Defined Benefit Pension Plans
Other comprehensive income (loss), net of tax:
Defined benefit plans	1,031	817	2,074	1,645
Other Postretirement Benefit Plans
Other comprehensive income (loss), net of tax:
Defined benefit plans	$ (71)	$ (65)	$ (151)	$ (135)